Significant research interest has been attracted to the development of metal-carbon composites and compounds, known as “covetic” materials, in an effort to improve their thermophysical, mechanical, and electrochemical properties. Such materials have a form of nanocarbon dispersed within a metal matrix. The term “covetic” is derived from “covalent” and “metallic”, in that there appears to be some type of hybrid bonding with attributes of covalent bonds and of metallic bonds between the metal and the carbon nanoparticles. Added carbon incorporates into the metal matrix and has an effect on several of the properties of the material, such as raising the melting point and significantly altering surface tension, thus porosity during solidification. Covetic materials can improve thermal, electrical, physical, and chemical properties (e.g., corrosion and oxidation resistance) relative to the base metal of the covetic material. Covetic materials have demonstrated the ability to withstand more than 1,500 degrees Celsius under an oxygen plasma lance without separation of carbon and metals. See, for example, the www website graphene-info (dot) com/covetics-hybrids-fuse-carbon-and-metal-strong-bonds. The effects of added carbon depend on the metal used. Copper-carbon composite, for example, can be formed by mechanically introducing carbon to copper metal by lamination, thereby imparting the resulting copper-carbon composite material with improved thermal conductivity over pure copper metal.
Processing methods have been developed for making covetic compositions. For example, metal-carbon compositions have been prepared via mixing carbon powder into melted metal (e.g., Cu, Al, Ag, Au, Fe, Ni, Pt) by stirring and applying a large current of hundreds of amperes (See U.S. Pat. No. 8,647,534), and then solidifying the mixture by cooling. Such metal-carbon compositions stay single phase upon remelting and solidification. Similar to conventional metals, these metal-carbon composites can be rolled into thin sheets, drawn into wires, or machined into parts.